Centralized administration is critical for efficient program management, coordination, and execution. Core A (Administrative Core) will provide all the logistic, scientific, managerial, financial, and biostatistics support to facilitate and to coordinate the studies described in this IPCAVD program. Core A will ensure that all the Projects and Cores function optimally and adhere to the timelines described in this grant. Core A will organize conference calls every two weeks and regular in-person meetings, maintain regulatory approvals, provide fiscal and logistic oversight, manage subcontracts, coordinate meetings with the Scientific Advisory Board (SAB) and NIAID Program Officials to support this IPCAVD program, and provide centralized biostatistics support for all preclinical and clinical studies for this IPCAVD program. This detailed administration and management structure will ensure that all the studies remain focused on the overall objective to develop Ad26/Env vaccines for HIV-1. To accomplish these goals, we propose the following five Specific Aims: Specific Aim 1. To coordinate communications, interactions, and operations among investigators, Projects, and Cores to facilitate the overall progress and goals of this IPCAVD program Specific Aim 2. To ensure and to maintain regulatory compliance Specific Aim 3. To provide detailed financial oversight and management Specific Aim 4. To coordinate meetings with the SAB and NIAID Program Officials Specific Aim 5. To provide centralized biostatistics support for this IPCAVD program